CHECKING FOR OXYGEN
SENSOR SWITCHING
CHECKING O2S HEATER
CHECKING IDLE AIR CON-
TROL MOTOR OPERATION
CHECKING ENGINE ME-
CHANICAL SYSTEMS
CHECKING EVAP EMISSION
SYSTEM
CHECKING EGR SYSTEM
CHECKING IAT SENSOR
CHECKING PNP SWITCH
3.4 USING THE DRBIIIT
Refer to the DRBIIItuser 's guide for instructions
and assistance with reading trouble codes, erasing
trouble codes, and other DRBIIItfunctions.
3.5 DRB ERROR MESSAGES AND BLANK
SCREEN
Under normal operation, the DRBIIItwill dis-
play one of only two error messages:
± User-Requested WARM Boot or User-
Requested COLD Boot.
This is a sample of such an error message display:
ver: 2.14
date: 26 Jul93
file: key_itf.cc
date: Jul 26 1993
line: 548
err: 0x1
User-Requested COLD Boot
Press MORE to switch between this display
and the application screen.
Press F4 when done noting information.
3.5.1 DRB IIITDOES NOT POWER UP
If the LED's do not light or no sound is emitted at
start up, check for loose cable connections or a bad
cable. Check the vehicle battery voltage (data link
connector cavity 16). A minimum of 11 volts is
required to adequately power the DRBIIIt.
If all connections are proper between the
DRBIIItand vehicle or other devices, and the
vehicle battery is fully charged, an inoperative
DRBIIItmay be the result of a faulty cable or
vehicle wiring. For a blank screen, refer to the
appropriate body diagnostics manual.
3.5.2 DISPLAY IS NOT VISIBLE
Low temperatures will affect the visibility of the
display. Adjust the contrast to compensate for this
condition.
4.0 DISCLAIMERS, SAFETY,
WARNINGS
4.1 DISCLAIMERS
All information, illustrations, and specifications
contained in this manual are based on the latest
information available at the time of publication.
The right is reserved to make changes at any time
without notice.
4.2 SAFETY
4.2.1 TECHNICIAN SAFETY INFORMATION
WARNING: ENGINES PRODUCE CARBON
MONOXIDE THAT IS ODORLESS, CAUSES
SLOWER REACTION TIME, AND CAN LEAD
TO SERIOUS INJURY. WHEN THE ENGINE IS
OPERATING, KEEP SERVICE AREAS WELL
VENTILATED OR ATTACH THE VEHICLE
EXHAUST SYSTEM TO THE SHOP EXHAUST
REMOVAL SYSTEM.
Set the parking brake and block the wheels before
testing or repairing the vehicle. It is especially impor-
tant to block the wheels on front-wheel drive vehicles;
the parking brake does not hold the drive wheels.
When servicing a vehicle, always wear eye pro-
tection, and remove any metal jewelry such as
watchbands or bracelets that might make an inad-
vertent electrical contact.
When diagnosing a powertrain system problem,
it is important to follow approved procedures where
11
GENERAL INFORMATION
ProCarManuals.com
Symptom:
* NO CRANK CONDITION
POSSIBLE CAUSES
BATTERY CIRCUIT RESISTANCE TOO HIGH
FUSED B(+) CIRCUIT OPEN
STARTER RELAY CONTROL CIRCUIT OPEN
STARTER RELAY OUTPUT CIRCUIT OPEN
CRANKSHAFT NOT ABLE TO ROTATE
STARTER MOTOR DEFECTIVE
PCM DEFECTIVE (NO CRANK CONDITION)
STARTER RELAY DEFECTIVE (RESISTANCE <=100 OHMS)
STARTER RELAY DEFECTIVE (RESISTANCE ABOVE 100 OHMS)
IGNITION SWITCH OUTPUT CIRCUIT OPEN
PARK/NEUTRAL SWITCH DEFECTIVE
TEST ACTION APPLICABILITY
1Note: Ensure the SKIM has proper communication and that there are no
SKIM DTC's present before continuing.
Ignition Off.
Disconnect the Starter Relay Connector.
Note: Check connectors - Clean/repair as necessary.
Warning: The Transmission must be in Park and the Parking Brake must be
on for the next step.
Warning: The engine may be cranked in the next step. Keep away from
moving parts.
Briefly connect a jumper wire between Starter Relay Output and Fused B(+)
Circuits.
Did the Starter Motor crank the Engine?All
Ye s®Go To 2
No®Go To 9
2 Ignition Off.
Disconnect the Starter Relay Connector.
Note: Check connectors - Clean/repair as necessary.
With a Voltmeter, measure the Fused B(+) Circuit.
Is the voltage above 11.6 volts?All
Ye s®Go To 3
No®Repair open Fused B(+) Circuit. (check Ignition Switch Fuse in
PDC).
Perform Powertrain Verification Test VER-1A.
296
STARTING
ProCarManuals.com
TEST ACTION APPLICABILITY
3 Ignition Off.
Ensure the Transmission is in Park.
With the DRB, read the Park/Neutral Position Switch.
Does the Switch show Park?All
Ye s®Go To 4
No®Repair Park/Neutral Switch.
Perform Powertrain Verification Test VER-1A.
4 Ignition Off.
Disconnect the Starter Relay Connector.
Note: Check connectors - Clean/repair as necessary.
Using an ohmmeter, test the Starter Relay Terminals for resistance.
Is the resistance above 100 ohms?All
Ye s®Replace the Starter Relay.
Perform Powertrain Verification Test VER-1A.
No®Go To 5
5 Ignition Off
Disconnect the Starter Relay Connector.
Note: Check connectors - Clean/repair as necessary.
With a voltmeter, probe Ignition Switch Output Circuit.
While attempting to crank the engine, read the Voltmeter.
Is the voltage above 10 volts?All
Ye s®Go To 6
No®Repair the open Ignition Switch Output (Start) Circuit.
Perform Powertrain Verification Test VER-1A.
6 Ignition Off.
Disconnect the Starter Relay Connector.
Disconnect the Powertrain Control Module.
Note: Check connectors - Clean/repair as necessary.
With an ohmmeter, test the Starter Relay Control Circuit for resistance.
Is the resistance above 5.0 ohms?All
Ye s®Repair the open Starter Relay Control Circuit.
Perform Powertrain Verification Test VER-1A.
No®Go To 7
7 Ignition Off
Disconnect the Powertrain Control Module.
Note: Check connectors - Clean/repair as necessary.
Warning: The Transmission must be in park and the Parking Brake must be
on for the next step.
Warning: The Engine may be cranked in the next step. Keep away form
moving Engine parts.
Connect a jumper wire between the Starter Relay Control Circuit and ground.
Briefly turn the Ignition to the crank position and then release.
Did the Engine crank?All
yes
Go To 8
no
Replace the Starter Relay.
Perform Powertrain Verification Test VER-1A.
297
STARTING
* NO CRANK CONDITION ÐContinued
ProCarManuals.com
